Anismus

Anismus is the inability to relax (or a paradoxical contraction of) the pelvic floor muscles during a bowel movement. There is no specific cause but could be related to increased pressure on the pelvic floor such as during vaginal childbirth, or from a history of injury to the pelvic floor from trauma or sexual abuse.

In order to have a successful bowel movement there is a coordinated interplay of increased pressure through the abdomen and a relaxation of the pelvic floor muscles. Dyssynergia is the lack of coordination of these actions, and can make having a bowel movement very difficult, leading to constipation, excessive straining and pain.

Pelvic floor physical therapy can use a variety of methods, including Biofeedback and manual feedback of the pelvic floor, to assist in learning better coordination and  relaxation of the pelvic floor muscles, therefore significantly reducing difficulty with bowel movements.